I Knew Before You Did
by God's Obsession
Summary: Arthur has been fascinated with magic since he was a boy, but never had a firm grasp on it. That is until he met a powerful warlock who came in a tall, gangly, and oh so tempting package. Now he'll never let Merlin go, no matter what.
1. Chapter 1

**Arthur knew from the moment the dark haired boy appeared before him, that there was something about him. Perhaps it was the insults he so easily slung without any intent of apology. Perhaps it was his thin and small frame that looked so easily breakable. Or maybe it was the way his eyes shone with emotion and something else. Something mysterious. Nevertheless, he annoyed Arthur and so he put the lad in the stocks. It was overly easy, being Prince. Arthur didn't expect to next see the boy in the palace, serving at the feast. Arthur had thought he was just passing through, or else visiting a family member inside Camelot, not becoming a servant in the palace. Arthur wasn't sure if he liked this or not. Still, he watched the boy carefully, trying to find out what it was about him. He smirked when the boy began noticing and seemed to squirm in place as if he could escape Arthur's gaze. But he wasn't so tame, even though it was clear he was doing his best to behave here. It was clear in the gaze he lifted to meet the Prince's, eyes a hard glare with his lips drawn into a frown that made them look so delicious. So bitable.**

 **It didn't take long for his suspicions to grow, after all, he had what he would call an intellectual fascination with magic. Not that he would ever dare admit it to anyone. Especially the fact that as a boy, Arthur had attempted to learn the ways of magic. He had failed though, and instead took to studying all he could of sorcerers and witches. He watched each execution, each prisoner, each found guilty with the utmost care, always going back to how he had seen them before they were caught, blending in with the people. Arthur had found that there was something about magic users in the way they stood, walked, or even looked. Something that held both power and fear. In some cases anger, but it was a way to tell of when they had something to hide, and Arthur made sure to learn it well. And the boy, Merlin, seemed very much like he was hiding magic. Well, at the very least he was hiding something. So Arthur decided to pull out all his hidden books and scrolls on sorcery. He went through them during his spare moments. However, something unexpected came to pass. Merlin had saved his life, and as a result, was appointed to be Arthur's manservant. He could see the clear dismay on the boy's face when his father, King Uther said it. Arthur matched the dismay, not liking having the boy thrust upon him, intruding upon his research. He had a manservant, a decent one that he had clear rules to abide by. Normally it wouldn't be too difficult to 'train' a new manservant into abiding by Arthur's strict rules, but Merlin.. Arthur knew Merlin wouldn't be so easily commanded.**

 **The Prince had time to think on it, though. In the end he came to a different conclusion that would be beneficial. With Merlin being so close to him, he could learn everything about the boy.**

 **Time passed and Arthur found that he really liked bullying Merlin. He loved the way the boy never backed down, would always come back with some insult or scathing comment. That wasn't the only thing he found though, for Arthur had watched the boy, hiding himself to catch Merlin in the act. And he did, several times. Though, it took Arthur a few times to believe it, how Merlin made things move without an enchantment. It was not a thing he heard of. Arthur thought it was impossible. For a while he thought that maybe the boy was just whispering so as not to be heard, but that proved false soon enough. So, Arthur returned to his scrolls and books until he found it. Tales of Emrys. A warlock, one born with great magic. It was a satisfactory discovery that had Arthur wearing a smirk for quite a while. Next was the fun part, telling Merlin that he knew.**

 **Arthur planned it out for some time, waiting for the opportune moment. It had been months since their first encounter and they had fallen into a sort of routine of bickering. Arthur had stopped watching Merlin as if he were a fish and somehow was drawn to him, into a strange sort of friendship that was entirely Merlin's fault. But Arthur liked it. There was power there, between them. Arthur was the Prince and Merlin a warlock. Either one could have power over the other, and they did in some ways. Merlin, however, could not use his power to command the respect that Arthur so easily had. It was endearing to watch him struggle with being just a servant though he truly was so much more. Arthur loved the way Merlin always challenged it, but slowly learned to work the system. And as much as he planned the moment he would tell Merlin he knew, he loved watching the boy come up with strange excuses for what accusations he made.**

" _Mer_ lin!" **The Prince called back at the trees, hands on hips as he waited for the gangly servant to appear. Honestly, even though he knew about Merlin's magic, sometimes Arthur worried he was an idiot anyways.**

"Sorry, sorry!" **Came the voice as Merlin stumbled into view.**

"Merlin, what is the use of you if you can't keep up? Come on!" **Arthur ordered, shaking his head and turning to go. Merlin frowned, hoisting the several rabbits Arthur had gotten higher up his shoulder.**

"Prat." **He mutters, trotting after the Prince.**

"Don't be such a girl. It's not that much farther to the horses." **Arthur returns with a roll of his eyes.**

"Oh yeah, well maybe next time you can carry all the dead animals across the forest for an entire day." **The boy sniped, tone conveying his clear irritation. Arthur shook his head.**

"It's your job, Merlin. Now shut up."

 **They got back to the castle an hour later. Merlin put the horses in the stables, delivered the rabbits to the kitchen, then scurried up to Arthur's room to help him change.**

"What took you so long?" **Arthur asked, arms crossed over his chest as his servant entered the room.** "Honestly, Merlin what do I pay you for?" **He asks, teasing, but keeping the grin off his face. Merlin rolled his eyes at the Prince, clearly tired, but rising to Arthur's words nevertheless.**

"To put up with you?" **He suggests saucily and Arthur fixes him with a hard stare. Merlin meets it easily until Arthur lets out a huff and shakes his head.  
** "I want to take a bath. Get it ready." **He saw the boy frown, but nod and start for the door. It was a little while later that Merlin had filled up a tub with water. Arthur came out from behind the screen, nothing but a towel around his hips. He reaches a hand to the water, feeling its temperature. Arthur raises a brow, raising his head to show Merlin his clearly dissatisfied expression.** "It's cold" **He states like a question as if Merlin should have a good answer.**

"It..It was warm when I-"

" _Was_ warm, Merlin. Not is. Do you really expect me to take a cold bath?" **He puts his hands on his hips, watching as Merlin's face furrowed into a frown. He was clearly tired and just didn't want to deal with this, but too bad.**

"By the time I get it warm again you won't want a bath, Sire, I don't know what you want me to do." **Clearly Merlin was going to just keep talking and complaining here, so Arthur decided to cut him off.**

"Then why don't you just use your magic to heat it?" **Arthur asks, and Merlin begins to respond with a snipe, but then stops completely as the words register. A smirk slides onto Arthur's lips as he watches Merlin's eyes go wide and mouth open wordlessly. He could see the panic clearly, and it sent a wonderful thrill down Arthur's spine. So adorable.** "What did you think I wouldn't know? Honestly, Merlin. I've known since the beginning." **Arthur steps to the other, leaning to whisper in Merlin's ear. He watched as goosebumps raised in the other's flesh. Another moment passes before Merlin's knees buckle. He would have fallen to the floor had Arthur not caught him, his hands grabbing Merlin's arms.** "Hey now." **Arthur says as he steadies him.**

"Wh-what are you going to do to me?" **He hears a small voice ask and turns to watch Merlin's face as the wide eyes stare into his own. Oh, that was a beautiful expression on the other. Arthur smirked again, letting one hand slide down to grip Merlin's hip while the other pressed into the small of the warlock's back. He hums, leaning in to nuzzle Merlin's neck.**

"I. Haven't decided yet." **He says, teasingly slow.** "But I fear it might be something bad if you don't heat up my bathwater. Eh, Merlin?" **Arthur feels Merlin's jerky nod and pulls back to watch the warlock's face. Merlin glances at Arthur for a moment before looking to the water. He hesitates a moment before murmuring a spell. His eyes glow gold for a moment and then it fades. Arthur turns to see steam rising and curling from the tub, and he grins.** "Beautiful." **He murmurs, his thumb stroking across Merlin's hip. He heard the sharp intake of Merlin's breath and grinned. Arthur pulled the towel from his hips, smirking as he handed it to Merlin then turned, showing off the muscles in his legs and back as he slipped into the water.** "Ahh, that's perfect." **He murmurs in appreciation for the soothing temperature. He glances back at Merlin, enjoying the slight red shade on his cheeks.** "Merlin." **He says raising an expectant eyebrow. The boy starts a little, raising his eyes from Arthur's chest and to meet Arthur's gaze.**

"Y-yes?" **He asks after swallowing. Arthur rolls his eyes, leaning back in the tub.**

"Get on with it. Wash me."

"W-wash you..?" **Merlin asks, looking at Arthur as if he was mad. The Prince held a cool gaze with Merlin until the male looked away with a mutter. Merlin pulled off his jacket and rolled up his sleeves before grabbing a cloth and kneeling beside the tub. He looked over Arthur doubtfully, but took the soap, wrapped it in the cloth, dipped it in the water, then hesitantly pressed it to Arthur's chest.**


	2. Chapter 2

"You must be completely mad." **Arthur says, closing the door behind him as he glares at his servant. Merlin glanced at the Prince and frowned.** "Using magic in front of the entire court, Merlin? What if someone saw? Hm? What if they suspected? You're too careless!"

"I'm not careless." **He mutters.** "I knew exactly what I was doing, Arthur, it's not like I haven't done it before." **Merlin crosses his arms over his chest, looking away with a glare. He was frustrated at Arthur. The patronizing was driving him mad. It felt like Arthur didn't trust him at all.**

" _Mer_ lin." **Arthur says, pausing before he strides over to Merlin, standing only an inch away. He reaches a hand to Merlin's chin, putting a finger under it. He turned Merlin's head to look the warlock in the eye.** "Unlike you, I care about your wellbeing. As much as I don't think you use it, I'd rather your head be on your shoulders. Understood?" **He gives Merlin an encouraging smile, holding the eye contact until Merlin conceded. The warlock gave up with a sigh, rolling his eyes.**

"Fine..next time I will be more careful. Happy now?" **He asks Arthur, raising his eyebrows. To which, Arthur smirks and begins taking steps forward.**

"Not quite yet.." **He murmurs, backing Merlin up until the warlock's back hit the wall. Merlin made a soft grunt, looking up at Arthur with new interest in his eyes. Arthur smirked a little more before he leaned in, taking Merlin's lips with his own. He used a crushing force, taking what he wanted from the kiss as Merlin kissed back desperately. His body pressed against Merlin's fully, pinning him to the wall, then he took one of the warlock's wrist, pinning it next to his head. Arthur's other hand held Merlin's cheek, tilting his chin up to deepen the kiss. The warlock groaned into Arthur's mouth, his free hand curling into the Prince's shirt. Merlin tugs on the shirt, as if he could get Arthur any closer. The kiss makes him breathless and dazed, so he doesn't feel Arthur's hand at his throat, pulling off the neckerchief. He doesn't realize until Arthur's mouth moved down, teeth scraping against Merlin's jaw. The warlock took in a shuddery breath, tilting his head back against the wall. He could feel Arthur's grin against his neck, the Prince pleased at the submission.**

"Arthur." **He gasps, hand sliding up into the blonde hair and gripping it. He knew what the other male was about to do. A moment later he felt teeth sink into the flesh of his skin. Merlin's back arched against the wall, pressing him into Arthur as the pain flashes through him and sends delightful shudders down his spine. He could feel his magic bubbling in with his pleasure that Arthur gave to him so teasingly. It had been a month since Arthur revealed he knew about Merlin's magic, and yet Arthur had done nothing more than tease Merlin in every hidden nook they would run into. Just teasing, never anything more than kissing and hickeys. It had been the most pent up month of his life, and Merlin wasn't sure if it felt worse than hiding his magic or not. However, right now, it felt amazing. Merlin's fingers pulled at the golden hair even after Arthur had moved on to suck marks into other parts of Merlin's neck. The warlock gasps as he feels the scrape of teeth against his jugular and when Arthur tongues the hollow of his neck. Merlin is sure that there are still some faint marks from the last time Arthur did this, but he knew the Prince only took those as reasons for pride.**

"You're so beautiful, Merlin.." **The soft, disbelieving whisper came, rousing Merlin from the sensations. He shivered at the warm breath the words brought to roll against his skin, swallowing in an instant.** "Can't believe you let me do this.. with all you have.. all that magic and you let me do this." **Arthur raises his head to look into the warlock's eyes, and Merlin gazes back. He could see the warmth, pride, and desire in Arthur's gaze. He could practically feel it. He could see the satisfaction. That Arthur had the most powerful sorcerer of all time completely willing. Completely docile. Merlin was still wild at times, still fierce and courageous, still defied Arthur when he believed Arthur was wrong, but here, in Arthur's chambers, he was Arthur's to control. Arthur smirked a little as he leaned in to take another kiss, this one shorter and much sweeter. Then he pulled away from the warlock, leaving Merlin to stare at him in confusion for another moment.** "What? I can't keep you from your chores forever. You haven't even started any yet." **Arthur teases the other, smirking when he saw Merlin's shock then indignation. He pushed himself from the wall, moving over and grabbing his neckerchief from the Prince then tying it back on.**

"Prat." **Merlin says with a look to Arthur as he then gathers up the laundry and walks out of the room. Arthur watches him go before letting out several chuckles of amusement.**


	3. Chapter 3

**For Merlin, the next day started early. He went to gather herbs for Gaius for an hour before he had to return to the castle. He pushes open the door to the prince's chambers and closes it behind himself. He sets the tray of food down then raises his head to look at Arthur. Still sleeping. Merlin sighed and shook his head, walking over to the window and drawing the curtains open. He heard the groan and smiled, turning around to see a sleepy Arthur glaring at him.**

"Oh, were you sleeping, my lord?" **Merlin asks with a big, teasing grin. The Prince kept glaring at him, but raised a hand, beckoning Merlin closer. Merlin's grin wavered a little, but he came closer. He got to the edge of the bed and stopped, but Arthur's arm shot out and grabbed him, pulling Merlin down next to Arthur. The boy gave a slight shout as he was pulled, having the action take him completely by surprise. His cheeks flushed and he turned to look at the male.** "Uh, A-Arthur?" **He asks, bewildered. The Prince just pulls Merlin close, wrapping an arm around him.**

"Shut up, Merlin." **He mumbled, closing his eyes to sleep once again.**

"B-b-but, Arthur, we need to-" **Merlin began his protest, only for Arthur to lean over and press a kiss to his lips. Arthur pulled back after a moment, looking down at a very red warlock.**

"Don't make me tell you again." **He says, almost smirking at Merlin before laying down and nuzzling into Merlin's neck.**

"Y-yes, Sire.." **Merlin stuttered out, a shiver running down his spine as he felt the Prince's breath on his skin. Merlin felt that there was no way he was going to fall back asleep like this, but after a few minutes, his eyes closed and he slipped into unconsciousness.**


	4. Chapter 4

**After that morning, there had been no more time for leisure. It was the turn of the season and spring was coming up on them, and with it, several feasts and festivities. The castle was filled with bustle and business, servants and nobles slipping through the halls alike. The Prince and his manservant were especially busy, Arthur having many duties to attend to. The king from a neighboring kingdom had come to visit, with the plan to review a treaty between the kingdoms that had been made the year prior. They would review it and discuss any changes they believed should be added to after the year they had to experience it. Then there would be a feast in celebration of, the anniversary of the treaty and the rearrangement of it. This was one duty that Arthur was particularly invested in. After all, it was the first treaty that his father had assigned to him to draw up. Of course, Arthur's drafts had been reviewed and edited several times, but it was, in essence, Arthur's treaty. As future king, Uther saw it fit for him to begin taking on more responsibility to make peace with the neighboring kings. However, this time, as it was a celebration, the king would be bringing with him members of his court and, his daughter. The weeks of preparation had Uther constantly informing Arthur of how beneficial it would be for Arthur to marry the princess. Arthur had several times reminded his father that he was not interested, but Uther ignored the protests. As it was, Merlin was also as busy, if not more, than Arthur. His regular chores had been added to. Gaius needed him for more deliveries and herb searches. He and a few other servants had been assigned to care for the guests coming in. And, of course, Merlin had to take care of Arthur's extra needs. Which were mostly getting the more fancy clothes that Arthur had to wear for important occasions ready. That involved, washing them carefully, mending them if they needed it, and more. Due to all the work going between them, they barely had a spare moment together.**

 **Merlin came bustling into the Prince's chambers, carrying several things; fresh clothes, lunch, and a few papers for Arthur to review. He stopped short as he saw the Prince at the window. Arthur had been leaning against the pillar, looking out on the busy square, but he turned his head as Merlin came into the room.**

"Ah, Sire.." **Merlin said, squirming slightly under Arthur's harsh gaze.**

"Do you not know how to knock?" **He asks, tone rather sharp. Merlin bites his lip, almost sighing. Arthur had gotten grumpier and grumpier as time went on, the stress getting to him. Though, he refused to talk to Merlin about it, which made the warlock increasingly frustrated with him.**

"Sorry…I didn't think you'd be in your chambers." **He mutters, moving more into the room. He sets the tray of food down on the table, the papers on Arthur's desk, then the clothes in the closet. He hadn't noticed that Arthur had moved until there were hands on his waist, snaking around him.** "Arthur!" **He says in a jump, trying to turn to look at the prince. However, the male held the warlock tight, bodies pressed together. He leaned in, nuzzling Merlin's nape for a moment before he began pressing kisses there. The warlock took in a shuddery breath, hands reaching up to grab Arthur's arms. The silence stayed between them, neither finding words they wanted to say at the moment. However, Merlin stays still for the prince, letting Arthur have his way. He could feel the prince's hot breath on his skin, making him shiver. A moan left his lips as the male's teeth nipped at a sensitive spot. Though, the moment didn't last long, Arthur pulling away and leaving Merlin with a flushed face.** "Arthur?" **Merlin questions, feeling a little hazy as he turns around to look at the male. The prince glances at Merlin, back in his position by the window as if he had never left.**

"Go get back to your chores." **He says dismissively, making Merlin frown. He was about to protest but stopped as he saw how tired Arthur looked. He let out a soft sigh, shaking his head a little bit. Merlin walked over to the Prince and leaned in, pressing a soft kiss to his lips then pulling away and nodding.**

"Yes, Sire."


End file.
